1. Field of the Invention
The present invention relates to a signal processing device which processes audio signals based on resonance components of resonators, such as sound boxes, shells, and sound boards of musical instruments.
The present application claims priority on Japanese Patent Application No. 2011-270035, the content of which is incorporated herein by reference.
2. Description of the Related Art
It is known that stringed instruments such as guitars can be equipped with electronic configurations which convert vibration propagating through strings into electric signals by use of pickups configured of piezoelectric elements. Electric signals may be amplified and then reproduced via speakers, thus producing sound (e.g. guitar sound) at a high volume. Sound reproduced based on electric signals detected by pickups may not substantially include resonance components which occur in sound boxes of guitars. For this reason, sound directly reproduced based on electric signals may convey an impression, in which the reproduced sound is heard differently from sound actually produced by an acoustic guitar, to listeners. To overcome this drawback, Patent Literatures 1 and 2 disclose a signal processing device which carries out convolution using an FIR (Finite Impulse Response) filter on electric signals, thus applying sound-box resonance of a guitar to reproduced sound.
The technology of Patent Literatures 1 and 2 is designed to carry out convolution so as to apply electric signals, corresponding to vibration propagating through strings of a stringed instrument with sound-box resonance sound of another stringed instrument, thus improving reproducibility of sound-box resonance sound. This technology needs a preliminary operation for analyzing impulse response using an impulse hammer in order to determine a transfer function representing a parameter for use in convolution in advance. Additionally, this technology needs an additional configuration such as a microphone for detecting sound. It is possible to improve convenience for users if a resonance component of a stringed instrument can be obtained without implementing a preliminary operation and an additional configuration.